The classic design of the Fisher Space Pen Bullet dates back to the 1940s. Today, the pen features an all-brass body and a specially-formulated, pressurized ink. The result is a nearly indestructible ballpoint pen that will write smoothly and dependably upside down, underwater, over grease, and in extreme cold and hot temperatures and has an estimated shelf life of 100 years. The pen is refillable.

The pen fits nicely in my pocket, but I've never had one of these pens that
didn't end up globs around the point. I gave up on these after purchasing about
five different refills and getting the same result.

Smooth finish, nice weight, and best of all it is virtually indestructible.Usually I would prefer my writing instruments a little longer but the center of
gravity in this pen makes for quite the comfortable grip.

I've had fun playing around with pressurized pens. This one works great to
consistently deliver a nice smooth flow of ink despite the writing surface. I
have yet to go fully underwater with this but writing on soaked pieces of paper
has been fun to try.